21997922 has 8 divisors (see below), whose sum is σ = 33051072. Its totient is φ = 10980900.

The previous prime is 21997861. The next prime is 21997931. The reversal of 21997922 is 22979912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21997922.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7454 + ... + 9977.

It is an arithmetic number, because the mean of its divisors is an integer number (4131384).

Almost surely, 2^21997922 is an apocalyptic number.

21997922 is a deficient number, since it is larger than the sum of its proper divisors (11053150).

21997922 is a wasteful number, since it uses less digits than its factorization.

21997922 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18064.

The product of its digits is 40824, while the sum is 41.

The square root of 21997922 is about 4690.1942390481. The cubic root of 21997922 is about 280.1951106094.

The spelling of 21997922 in words is "twenty-one million, nine hundred ninety-seven thousand, nine hundred twenty-two".